1. Field of the Invention
This invention pertains to lead locking devices and methods for locking onto a lead, and more particularly to lead locking devices and methods for locking onto and removing a lead, such as a pacemaker lead, from a patient""s body.
2. Description of Related Art
Various medical procedures attach wire-like devices to internal portions of a person""s body, such as an electrical lead for a pacemaker or a catheter. Pacemaker leads are electrically conducting wires which run to an electrode that is attached to an inner wall of a person""s heart. Pacemaker leads are typically a coil of wire enclosed in an outer cylindrical sheath of electrically insulating material. The coil of wire usually leaves a hollow space running down the center of the pacing lead (a xe2x80x9clumenxe2x80x9d).
Pacing leads are usually implanted with the intention that they will remain in the patient for several years. During such time, fibrous tissue grows over the electrode and portions of the lead. Pacing leads are often provided with additional barb-like structures or a corkscrew type of structure to encourage adhesion to the inner wall of the patient""s heart.
Pacing leads sometimes fail or it is sometimes desirable to place an electrode at a different position from a previous position. It is then necessary to determine what should be done with the unused pacing leads. Both the removal of a pacing lead and leaving it in the patient entail associated risks. Leaving the pacing lead in the patient can increase the chances of infection, interfere with the additional pacing leads, or cause additional complications. On the other hand, removing pacing leads can cause severe, and possibly fatal, damage to the patient""s heart.
Numerous devices have thus been developed that can be inserted into the lumen of a pacing lead to be attached to the pacing lead close to the electrode in order to apply traction to the end of the lead that is close to the electrode. A series of patents to Goode et al (U.S. Pat. Nos. 4,943,289; 4,988,347; 5,011,482; 5,013,310; and 5,207,683) disclose various devices which attach to the pacing lead at a localized region close to the electrode. Peers-Trevarton (U.S. Pat. No. 4,574,800), Hocherl et al (U.S. Pat. No. 5,549,615) and McCorkle (U.S. Pat. Nos. 4,471,777 and 4,582,056) disclose similar devices which attach to a pacing lead close to the electrode. However, all of these devices have a disadvantage that they attach to the pacing lead in a localized area. Applying traction to the pacing lead and/or pacing lead removing devices according to the prior art can result in the pacing lead becoming distorted and/or breaking before it can be removed from the patient. In addition, the prior art devices rely on either a form of entanglement with the coiled wire of the pacing lead, or some form of local distortion to the coil of the pacing lead in order to maintain a firm grip with the pacing lead removing apparatus while traction is applied to the apparatus. Consequently, this makes it difficult or impossible to remove a conventional device from the pacing lead in order to abort or restart the pacing lead removing procedure.
The expandable portions of the conventional devices also make it difficult or impossible to use other lead removing equipment and procedures in conjunction with those devices. For example, a substantially cylindrical and flexible catheter which has a central lumen is often slid over the pacing lead such that the pacing lead passes through the lumen of the catheter and the leading edge of the catheter is used to free fibrous growth from the pacing lead. Laser catheters are also known to slide over a pacing lead in which laser light is transmitted along the catheter in order to cut away fibrous tissue as the laser catheter is advanced along the pacing lead. It is also known to use a pair of telescoping catheters, both of which slide over the pacing lead. Consequently, it is also desirable to have a pacing lead removing device which can attach internally to the pacing lead so as not to obstruct a catheter or laser catheter which may be used in conjunction with the pacing lead removing device.
Accordingly, it is an object of this invention to provide a lead locking device which is insertable into a lumen of a lead and which engages and forms a grip with an extended portion of the inner region of the lead.
It is another object of this invention to provide a lead locking device which is insertable into a lumen of a lead and which engages and forms a grip with an extended portion of the inner region of the lead including at least a proximal portion.
It is another object of this invention to provide a lead locking device which is insertable into a lumen of a lead and engages the lead substantially along the entire length of the lead to form a grip with the lead.
It is another object of this invention to provide a lead locking device and catheter combination for removing a lead, such as a pacemaker lead, from a patient""s body.
It is another object of this invention to provide a method of removing a pacing lead by attaching a lead locking device to an extended portion of a lead within the lumen of the lead.
It is another object of this invention to provide a method of removing a lead from a patient""s body by attaching a lead locking device along substantially the entire length of a lead.
The above and related objects of this invention are realized by providing a lead locking device that has a lead insertion member having a proximal end and a distal end. The lead insertion member has a lead engaging assembly that defines a lumen extending along a longitudinal axis between the distal end and the proximal end of the lead engaging assembly, a mandrel disposed in the lumen of the lead engaging assembly extending along substantially the entire length of the lumen and protruding beyond the most proximal end of the lead insertion member. The mandrel includes a distal portion in slidable contact with at least a portion of the lead engaging assembly. The lead engaging assembly has a first configuration while being inserted into a lumen of a lead and a second configuration while engaging the lead from within the lumen of the lead. The lead engaging member has at least two expansion jaws that, in the first configuration, define a substantially cylindrical body. The at least two expansion jaws translate radially outwardly from the longitudinal axis to engage the lumen of the lead when in the second configuration.
In another embodiment of the invention, a lead locking device has a lead engaging member having a distal end and a proximal end. The lead engaging member includes a series of juxtaposed sections, each section forming a through hole and each through hole being aligned with an adjacent through hole of an adjacent section to define a bore hole extending along a longitudinal axis between the distal end and the proximal end; a mandrel disposed in the bore hole and fixedly attached to at least one of the sections of the lead engaging member, the mandrel extending along substantially the entire length of the bore hole and protruding beyond the most proximal end of the lead engaging member. The lead engaging member has a first configuration while being inserted into a lumen of a lead and a second configuration while engaging the lead from within the lumen of the lead.
In another embodiment of the invention, a method of removing a lead implanted in a patient""s body includes inserting a lead locking device into a lumen defined by the lead, the lead locking device comprising a lead engaging member that extends along substantially the entire length of the lead, the lead engaging member having a narrower overall radial dimension in a relaxed configuration than in a radially torqued configuration. The lead engaging member is in the relaxed configuration during the insertion of the lead locking device. The method also includes applying a torque to the lead engaging member, wherein applying the torque to the lead engaging member causing the lead engaging member to have an overall radial dimension that is substantially equal to an inner diameter of the lumen of the lead. The method also includes applying traction to the lead locking device. The lead engaging member engages the lead along substantially the entire longitudinal length of the lead.
In another embodiment of the invention, a lead locking device has a hypotube defining a plurality of openings therein, the hyptotube having a longitudinal axis extending between a distal end and a proximal end thereof; and a lead engaging member disposed in the hypotube, the lead engaging member including a plurality of bristles radially extending from a mandrel, the bristles being resiliently biased in an outward radial direction of the longitudinal axis, the mandrel being disposed generally along the longitudinal axis and extending along substantially the entire length of the hypotube and protruding beyond the most proximal end of the hypotube. The lead engaging member has a first configuration while being inserted into a lumen of a lead and a second configuration while engaging the lead from within the lumen of the lead.
In another embodiment of the invention, a method of removing a lead implanted in a patient""s body includes inserting a lead locking device into a lumen defined by the lead, the lead locking device having a hypotube that has a plurality of openings formed therein, and a lead engaging member disposed in the hypotube. The lead engaging member includes a plurality of bristles radially extending from a mandrel, the bristles being resiliently biased in the outward radial direction of the longitudinal axis, and disposed within the hypotube in a first configuration for inserting the lead locking device into the lead. The method also includes applying an axial force to the mandrel so that bristles of the lead engaging member protrude from the openings to engage the lead. The overall radial dimension of the distal ends of the bristles is substantially equal to an inner diameter of the lumen of the lead. The method further includes applying traction to the lead locking device. The lead engaging member engages the lead along substantially the entire longitudinal length of the lead.
In another embodiment of the invention, a lead locking device has a mandrel and a lead engaging member that has a distal end and a proximal end. The lead engaging member includes a plurality of radially expandable elastic members disposed around the mandrel. The mandrel extends along a longitudinal axis between the distal end and the proximal end, the mandrel protruding beyond the most proximal end of the lead engaging member. The lead engaging member has a first configuration while being inserted into a lumen of a lead and a second configuration while engaging the lead from within the lumen of the lead.
In another embodiment of the invention, a method of removing a lead implanted in a patient""s body includes inserting a lead locking device into a lumen defined by the lead. The lead locking device has a plurality of radially expandable elastic members disposed around a mandrel, each of the plurality of radially expandable elastic members having a smaller radial dimension in a relaxed configuration than in a compressed configuration, wherein the elastic members are in a relaxed configuration during the insertion of the lead locking device. The method also includes applying an axial compressive force to the elastic members so that the elastic members of the lead engaging member extend radially outwardly to engage the lumen of the lead in the compressed configuration, wherein the transverse diameter of some of the elastic members in the compressed configuration are substantially equal to an inner diameter of the lumen of the lead. The method further includes applying traction to the lead locking device. The lead engaging member engages the lead along substantially the entire longitudinal length of the lead.